How to add indexes if they do not already exist

Hi Tim,

I’ve been trying to add indexes to existing columns in postgres database.

I think I found a way to add them using (I found this documented in the knex source):

table.index('column_name')

The problem is that the indexes may already exist in which case I get the following error:

Error: model ensureSchema { [error: relation "models_column_name_index" already exists]
  name: 'error',
  length: 104,
  severity: 'ERROR',
  code: '42P07',
  detail: undefined,
  hint: undefined,
  position: undefined,
  internalPosition: undefined,
  internalQuery: undefined,
  where: undefined,
  file: 'index.c',
  line: '777',
  routine: 'index_create' }

I’ve been working at trying to do this for around 6 hours using the Knex.schema.table(table_name, (table) -> ).exec(callback) inner block and feel like I must be missing something. I originally tried to find a way to get access to a column builder, but I couldn’t use the table.type(column_name).index() syntax because the column already existed and even if it did, I assume that I would get the same index already existing error.

Is there a lower level way to check for indexes existing? Ideally, it would be general purpose enough that you could check if a column was indexed, primary, nullable, unique, etc.

Thank you in advance for any advice and pseudo code.

[yamikuronue]

I agree, this is highly unintuitive. The docs seem to imply that the callback is only being called if the table did not exist, so it can be created; otherwise, why would you need to call the table creation API anyway?

[bennycode]

I also expected that knex.schema.createTableIfNotExists doesn’t run the callback if the table already exists. So the official workaround is to check with hasTable beforehand?